Question 1

The four bases on the DNA molecule are paired with A opposite T and G opposite C.

Accepted Answer

In the DNA molecule, adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C) through hydrogen bonding, forming the base pairs that make up the double helix structure.

Question 2

DNA analysts are able to examine samples containing as few as ________ cells for an STR profile.
A)18
B)36
C)180
D)800

Accepted Answer

DNA analysts can examine samples containing as few as 18 cells for an STR (Short Tandem Repeat) profile, thanks to advancements in DNA amplification techniques like PCR (Polymerase Chain Reaction).

Question 3

Small amounts of blood are best submitted to a crime laboratory:
A)Immediately while still wet.
B)In a druggists fold.
C)After dried.
D)After removal from surface of deposition and rehydration.

Accepted Answer

Small amounts of blood are best submitted to a crime laboratory after they have dried. This prevents the degradation of the sample and reduces the risk of bacterial growth or other contamination that can occur in wet samples. Drying the sample also makes it easier to handle and transport.

Question 4

PCR are regions of a chromosome that contain multiple copies of a core DNA sequence arranged in a repeating fashion.

Accepted Answer

PCR (Polymerase Chain Reaction) is a laboratory technique used to amplify and make millions of copies of a specific DNA segment, not regions of a chromosome with repeating sequences.

Question 5

How should blood-containing clothes from a victim be packaged?
A)In an airtight metal container
B)In an airtight clear plastic container
C)In a metal paint can
D)In breathable paper after blood has dried

Accepted Answer

Blood-containing clothes should be allowed to dry and then packaged in breathable paper to prevent the growth of mold and bacteria, which can degrade DNA and other forensic evidence. Airtight or non-breathable containers can trap moisture, promoting the growth of mold and bacteria.

Question 6

Longer DNA strands are more stable and less subject to degradation than shorter strands.

Accepted Answer

Longer DNA strands are not inherently more stable and can be more susceptible to damage and degradation due to their increased length offering more targets for cleavage and harmful interactions. Stability is influenced by many factors, including sequence composition and environmental conditions, not just length.

Question 7

The amount of DNA material required for STR analysis is ________ the amount of DNA required for RFLP analysis.
A)The same as
B)Greater than
C)Less than
D)None of the above

Accepted Answer

STR analysis requires less DNA material compared to RFLP analysis, making it more suitable for cases where the DNA sample is limited or degraded.

Question 8

Mitochondrial DNA analysis is significantly more sensitive than nuclear DNA profiling.

Accepted Answer

Mitochondrial DNA analysis is more sensitive because it can be performed on smaller or more degraded samples than nuclear DNA profiling, as there are many more copies of mitochondrial DNA per cell.

Question 9

The greater the number of STRs characterized, the smaller the frequency of occurrence of the analyzed sample in the general population.

Accepted Answer

STRs (Short Tandem Repeats) are highly variable regions in the DNA. The more STR locations that are characterized, the more unique the genetic profile becomes, thus decreasing the likelihood of finding an identical profile in the general population.

Question 10

A short tandem repeat (STR)is a region of a DNA molecule that contains short segments consisting of 50-100 repeating base pairs.

Accepted Answer

A short tandem repeat (STR) typically consists of repeating units of 2-6 base pairs in length, not 50-100 base pairs.

Question 11

A conventional STR profile emanating from a mixture of DNA from male donors yields four peaks or bands for each locus present. How many peaks or bands would you normally expect for each locus if a Y-STR profile is performed on the same sample?
A)One
B)Two
C)Three
D)Four

Accepted Answer

The answer of A conventional STR profile emanating from a...

Question 12

Mitochondrial DNA is found in the nucleus of each cell and is inherited from both parents.

Accepted Answer

Mitochondrial DNA is located in the mitochondria outside the nucleus and is typically inherited exclusively from the mother.

Question 13

Proteins are formed by linking a combination of nucleotides.

Accepted Answer

Proteins are formed by linking a combination of amino acids, not nucleotides. Nucleotides are the building blocks of nucleic acids like DNA and RNA.

Question 14

A typical STR DNA type emanating from a single individual shows a ________-band pattern.
A)1
B)2
C)3
D)0

Accepted Answer

A typical STR (Short Tandem Repeat) DNA type from a single individual usually shows a 2-band pattern because humans are diploid organisms, inheriting one allele from each parent at each locus.

Question 15

STRs normally consist of repeating sequences of:
A)13-17 bases.
B)18-2 bases.
C)3-7 bases.
D)8-12 bases.

Accepted Answer

STRs (Short Tandem Repeats) typically consist of repeating sequences of 3-7 bases. These short sequences are repeated numerous times in a row on the DNA strand, and they are a key component of genetic fingerprinting techniques due to their high variability among individuals.

Question 16

Electrophoresis can be used in the crime lab to analyze:
A)DNA.
B)Proteins.
C)dried blood.
D)All of the above

Accepted Answer

Electrophoresis is a technique used to separate molecules based on size and charge, making it useful for analyzing DNA, proteins, and components of dried blood in forensic investigations.

Question 17

________ region(s)of mitochondrial DNA have been found to be highly variable in the human population for forensic determinations.
A)1
B)2
C)3
D)4

Accepted Answer

The mitochondrial DNA regions that are highly variable and used for forensic determinations are the hypervariable regions I and II (HV1 and HV2). These regions are particularly useful for identifying individuals because of their high mutation rate, which leads to significant variability among individuals.

Question 18

Each cycle of the DNA Thermal Cycler takes approximately:
A)30 seconds.
B)4 hours.
C)2 hours.
D)2 minutes.

Accepted Answer

Each cycle of a DNA Thermal Cycler, which is used in PCR (Polymerase Chain Reaction) processes, typically takes about 2 minutes. This includes the denaturation, annealing, and extension steps.

Question 19

Tandem repeats are useful for forensic scientists because they provide a way to distinguish one individual from another through DNA typing.

Accepted Answer

Tandem repeats, also known as short tandem repeats (STRs) or microsatellites, vary greatly among individuals, making them highly useful in forensic science for DNA profiling to distinguish one individual from another.

Question 20

James Watson and Francis Crick are credited with discovering the structure of DNA.

Accepted Answer

James Watson and Francis Crick are credited with discovering the double helix structure of DNA in 1953, which is fundamental to understanding its function in biological inheritance.

Quiz 16: DNA: The Indispensable Forensic Science Tool

The four bases on the DNA molecule are paired with A opposite T and G opposite C.

DNA analysts are able to examine samples containing as few as ________ cells for an STR profile.

Small amounts of blood are best submitted to a crime laboratory:

PCR are regions of a chromosome that contain multiple copies of a core DNA sequence arranged in a repeating fashion.

How should blood-containing clothes from a victim be packaged?

Longer DNA strands are more stable and less subject to degradation than shorter strands.

The amount of DNA material required for STR analysis is ________ the amount of DNA required for RFLP analysis.

Mitochondrial DNA analysis is significantly more sensitive than nuclear DNA profiling.

The greater the number of STRs characterized, the smaller the frequency of occurrence of the analyzed sample in the general population.

A short tandem repeat (STR)is a region of a DNA molecule that contains short segments consisting of 50-100 repeating base pairs.

A conventional STR profile emanating from a mixture of DNA from male donors yields four peaks or bands for each locus present. How many peaks or bands would you normally expect for each locus if a Y-STR profile is performed on the same sample?

Mitochondrial DNA is found in the nucleus of each cell and is inherited from both parents.

Proteins are formed by linking a combination of nucleotides.

A typical STR DNA type emanating from a single individual shows a ________-band pattern.

STRs normally consist of repeating sequences of:

Electrophoresis can be used in the crime lab to analyze:

________ region(s) of mitochondrial DNA have been found to be highly variable in the human population for forensic determinations.

Each cycle of the DNA Thermal Cycler takes approximately:

Tandem repeats are useful for forensic scientists because they provide a way to distinguish one individual from another through DNA typing.

James Watson and Francis Crick are credited with discovering the structure of DNA.